SwiftUI view that displays content gradually

AnimatedText.swift

//
//  AnimatedText.swift
//
//  Created by Kauntey Suryawanshi on 23/07/24.
//

import SwiftUI

struct AnimatedText: View {
    enum Speed {
        case fast, normal, slow

        var duration: Duration {
            switch self {
            case .fast: .milliseconds(50)
            case .normal: .milliseconds(100)
            case .slow: .milliseconds(200)
            }
        }
        /// Newline takes a longer wait
        var durationNewLine: Duration {
            switch self {
            case .fast: .milliseconds(500)
            case .normal: .milliseconds(1000)
            case .slow: .milliseconds(2000)
            }
        }
    }

    let text: AttributedString
    let speed: Speed
    let wait: Duration

    @State private var endIndex: AttributedString.Index

    init(_ text: AttributedString, speed: Speed = .normal, wait: Duration = .zero) {
        self.text = text
        self.wait = wait
        self.speed = speed
        endIndex = self.text.startIndex
    }

    init(_ text: String, speed: Speed = .normal, wait: Duration = .zero) {
        self.init(AttributedString(text), speed: speed, wait: wait)
    }

    var body: some View {
        Group {
            Text(AttributedString(text[text.startIndex ..< endIndex]))
            + Text(AttributedString(text[endIndex ..< text.endIndex]))
                .foregroundColor(.clear)
        }
        .animation(.default, value: endIndex)
        .task {
            try? await Task.sleep(for: wait)
            for i in text.characters.indices {
                if text.characters[i].isNewline {
                    endIndex = i
                    try? await Task.sleep(for: speed.durationNewLine)
                } else if text.characters[i].isWhitespace || text.characters.endIndex == i {
                    endIndex = i
                    try? await Task.sleep(for: speed.duration)
                }
            }
            endIndex = text.endIndex
        }
    }
}

#Preview {
    var attrString = AttributedString("Mark my words\n")
    attrString.font = Font(NSFont.systemFont(ofSize: 21))
    attrString.append(AttributedString("Long term capital gains for all asset classes is going to be 12.5%. You may worry about your stocks and equity funds. Actually that is very less of your concern.\nYou pay 2.5% more  than earlier now."))

    return VStack(alignment: .leading, spacing: 10) {
        AnimatedText(attrString, speed: .normal)
    }
    .padding()
    .frame(width: 500, height: 500)
}

Demo

Untitled.mov

This SwiftUI view displays text gradually.